package mylist;


import java.util.Arrays;

public class MyArrayList implements Ilist{

    public int[] elem;
    public int usedSize;
    public static final int DEFAULT_SIZE=10;
    public MyArrayList(){
        this.elem = new int[DEFAULT_SIZE];
    }
    public MyArrayList(int capacity){
        this.elem = new int[capacity];
    }
    /*
    遍历顺序表
     */
    @Override
    public void display() {
        for(int i = 0;i<this.usedSize;i++){
            System.out.print(this.elem[i]+" ");
        }
        System.out.println();
    }
    @Override
    public void add(int data) {
        checkCapacity();
        this.elem[usedSize]=data;
        this.usedSize++;
    }
    @Override
    public boolean isFull(){
        return usedSize==elem.length;
    }
    @Override
    public void add(int pos, int data) {
        try{
            checkPosOnAdd(pos);
        }catch (PosIllegality e){
            e.printStackTrace();
            return;
        }
        checkCapacity();

        //1.从最后一个有效的数字开始往后移动        2.i<pos结束
        for(int i = usedSize-1;i>=pos;i--){
            elem[i+1] =elem[i];
        }


        //3.存放元素到pos位置
        elem[pos] = data;
        //4.usedSize++
        usedSize++;
    }
    private void checkPosOnAdd(int pos)throws PosIllegality{
        if(pos<0||pos>this.usedSize) {
            System.out.println("不合法");
          throw new PosIllegality("插入元素下标异常"+pos);
        }
    }
    private void checkCapacity(){
        if(isFull()){
            elem = Arrays.copyOf(elem,elem.length*2);

        }
    }
    @Override
    public boolean contains(int toFind) {
        if(isEmpty()) {
            return false;
        }
        for(int i = 0;i<usedSize;i++){
            //如果查找引用类型，重写eauals方法
            if(elem[i]==toFind){
                return true;
            }
        }
        return false;
    }
    @Override
    public boolean isEmpty(){
        return usedSize==0;
    }

    @Override
    public int indexOf(int toFind) {
        if(isEmpty()) {
            return -1;
        }
        for(int i = 0;i<usedSize;i++){
            //如果查找引用类型，重写eauals方法
            if(elem[i]==toFind){
                return i;
            }
        }
        return -1;
    }

    @Override
    public int get(int pos) throws MyArrayListEmpty{
        checkPosOnGetAndSet(pos);
        if(isEmpty()){
            throw new MyArrayListEmpty("获取指定下标元素时"+
                    "顺序表为空！");
        }
        return elem[pos];
    }
    private void checkPosOnGetAndSet(int pos)throws PosIllegality{
        if(pos<0||pos>=this.usedSize) {
            System.out.println("不合法");
            throw new PosIllegality("获取指定下标的元素异常"+pos);
        }
    }
    @Override
    public void set(int pos, int value) {
    checkPosOnGetAndSet(pos);
    elem[pos] = value;
    }

    @Override
    public void remove(int toRemove) {
        //1.找到要删除的数字i
        int index = indexOf(toRemove);
        if(index==-1){
            System.out.println("没有这个数字");
            return;
        }
        //2.i =  i+1,i++
        for(int i=index;i<usedSize-1;i++){
            elem[i]=elem[i+1];
        }
        //3.usedSize--
        usedSize--;
    }

    @Override
    public int size() {
        return this.usedSize;
    }

    @Override
    public void clear() {
        this.usedSize = 0;
    }
}
